A353765 - OEIS

A353765

Numbers k for which A353749(k) is a multiple of A353749(sigma(k)), where A353749(k) = phi(k) * A064989(k), and A064989 shifts the prime factorization one step towards lower primes.

1, 3, 5, 15, 27, 459, 819, 2295, 13923, 69615, 361179, 3282147, 6140043, 16410735, 30700215, 99558459, 277788987, 497792295, 1388944935

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Question: Does every term need to be odd? Could there be any other non-multiples of 3 than a(1) and a(3)?

If it exists, a(20) > 2^32.

LINKS

Table of n, a(n) for n=1..19.

Index entries for sequences where odd perfect numbers must occur, if they exist at all

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

CROSSREFS

Cf. A000010, A000203, A006872, A062401, A064989, A336549, A336550, A353757, A353761.

Positions of 1's in A353763. Cf. also A353764.

Conjectured to be a subsequence of A353758.

Sequence in context: A146244 A146457 A051044 * A358584 A003536 A340670

Adjacent sequences: A353762 A353763 A353764 * A353766 A353767 A353768

KEYWORD

nonn,more

AUTHOR

Antti Karttunen, May 10 2022

STATUS

approved